Temporomandibular joint dislocation after use of a laryngeal mask airway

Abstract

Use of the laryngeal mask airway has not previously been reported to be associated with bilateral temporomandibular joint (TMJ) dislocation. A size 4 laryngeal mask airway was inserted, without difficulty, in a 45-year-old female undergoing breast surgery. As she regained consciousness in the postoperative recovery room, it was noticed that she was unable to close her mouth, complained of bilateral sore temporomandibular regions and her speech was mumbled. Her jaw was not deviated. Anterior bilateral TMJ dislocation was diagnosed clinically. There was no history of previous TMJ dislocation. Successful reduction was done with manipulation directed inferiorly and posteriorly using propofol for sedation. A relocation ‘clunk’ was felt bilaterally and heard. On awakening, the patient was able to close her mouth, move her jaw without difficulty and talk normally. Relocation was confirmed with an orthopantomogram. Use of a laryngeal mask airway predisposes to pharyngolaryngeal trauma [1], sore throat and dysphagia [2], but has not previously been reported to be associated with bilateral TMJ dislocation. There are, however, several reports of bilateral TMJ dislocation associated with anaesthesia [3, 4]. TMJ dislocation occurred with wide opening of the jaw to place an oropharyngeal airway and nasogastric tube in a mechanically ventilated patient undergoing exploratory laparotomy [3]. This incident was preceded by uneventful laryngoscopy for tracheal intubation. TMJ dislocation was reported after thiopental induction but prior to laryngoscopy for tracheal intubation [4]. Wide mouth opening predisposes to bilateral anterior TMJ dislocation, occurring when the condylar heads are forced to a position anterior to the articular eminence away from their resting position within the glenoid fossa. The patient is then unable to close their mouth (the jaw is held in a lowered but central position), has difficulty speaking and experiences pain in the TMJ region bilaterally [5]. A jaw thrust to lift the pharyngeal structures anteriorly facilitates the passage of a laryngeal mask airway into the hypopharynx with less epiglottic contact [6]. Loss of motor response to jaw thrust (to assess depth of anaesthesia for laryngeal mask airway inertion) [7] may predispose to TMJ dislocation, by anteriorly displacing the mandible [8].